Method of controlling exothermic reaction of an exothermic composition, the exothermic composition, an exothermic device and an application pad

Abstract

An exothermic composition, enclosed in a container at least part of which is gas-permeable, generates heat in the presence of air. The exothermic composition includes a water absorber having a water absorptive ability reversibly variable with temperature variations. The water absorber releases adsorbed water, at above a predetermined temperature, to increase free moisture around a metal powder, thereby retarding the exothermic reaction.

What is claimed is: 
     
       1. A method of controlling an exothermic reaction of an exothermic device, comprising forming an exothermic composition, during forming said exothermic composition comprising, as essential components thereof, a metal powder, a metallic chloride, and water mixing a water absorber having a water absorptive ability reversibly variable with temperature variations into said exothermic composition, enclosing said exothermic composition and water absorber mixture in a container in which at least a part of said container is gas-permeable, whereby heat is formed when said mixture is in contact with air and said water absorber releases adsorbed water above a predetermined temperature, to increase free moisture, thereby retarding the exothermic reaction. 
     
     
       2. A method of controlling an exothermic reaction of an exothermic device as defined in claim 1, wherein following a decrease in exothermic temperature due to the retardation of the exothermic reaction based on a release of the absorbed water from said water absorber, the exothermic reaction resumes due to the absorption of water by said water absorber. 
     
     
       3. A method of controlling an exothermic reaction of an exothermic device as defined in claim 1, wherein said water absorber comprises a water-soluble cellulose ether. 
     
     
       4. A method of controlling an exothermic reaction of an exothermic device as defined in claim 1, further comprising mixing a water retainer comprising a water absorptive polymer for holding water into the exothermic composition, the water absorbed by said water retainer being gradually released. 
     
     
       5. An exothermic device comprising, as essential components thereof, a metal powder, a metallic chloride, water, and a water absorber having a water absorptive ability reversibly variable with temperature variations due to an exothermic reaction. 
     
     
       6. An exothermic device as defined in claim 5, further comprising a catalyst and/or a pH regulator. 
     
     
       7. An exothermic device as defined in claim 5, further comprising a water retainer. 
     
     
       8. An exothermic device as defined in claim 7, wherein said water retainer is a water-absorptive polymer other than a water-soluble cellulose ether. 
     
     
       9. An exothermic device as defined in claim 5, further comprising an exothermic reaction auxiliary for promoting the exothermic reaction. 
     
     
       10. An exothermic device as defined in claim 5, wherein said water absorber having a water absorptive ability reversibly variable with temperature variations due to the exothermic reaction is a water-soluble cellulose ether. 
     
     
       11. An exothermic device as defined in claim 5, in which said device is enclosed in a flat pouch having at least one gas-permeable surface. 
     
     
       12. An exothermic device as defined in claim 11, wherein said device contains a far infrared radiator. 
     
     
       13. An application pad comprising an exothermic device including as essential components thereof, a metal powder, a metallic chloride, water, and a water absorber having a water absorptive ability reversibly variable with temperature variations due to an exothermic reaction, said exothermic device being enclosed in a flat pouch having at least one gas-permeable surface, and further including an adhesive layer formed on one surface of the flat pouch. 
     
     
       14. An application pad as defined in claim 13, in which said flat pouch further comprises skin absorbable medication mixed in said adhesive layer. 
     
     
       15. An application pad as defined in claim 13, further comprising a far infrared radiator contained or carried in at least one of said exothermic composition, said pouch and said adhesive layer and/or between said pouch and said adhesive layer. 
     
     
       16. An application pad as defined in claim 13, further comprising a magnetic element contained or carried in at least one of said exothermic composition, said pouch and said adhesive layer and/or between said pouch and said adhesive layer. 
     
     
       17. An application pad as defined in claim 13, in which said pouch further comprises skin absorbable medication provided between said pouch and said adhesive layer.